Project summary Though magnetic resonance imaging (MRI) has historically suffered from substantial image artifacts in the presence of metallic implants, recently developed Three-Dimensional Multi-Spectral Imaging (3D-MSI) technol- ogy has signi?cantly overcome many of these technical challenges. Extensive clinical evaluation of 3D-MSI techniques has demonstrated a robust improvement relative to conventional imaging assessments for a variety of complications found in the near vicinity of metal devices. Despite these initial successes, a selection of routine MRI capabilities remain infeasible near metallic instrumentation. One of these capabilities is diffusion-weighted imaging, which can substantially impact the assessment of pathologies that include cancer, necrosis, and nerve impingement. This study's primary research goal is to explore and re?ne the technical alternatives for diffusion-weighted imaging in the near vicinity of metallic hardware. We propose to expand upon promising preliminary developments of diffusion-weighting in multi-spectral imaging. In this expansion, the previously explored non-Cartesian non-CPMG diffusion-weighted PROPELLER multi-spectral imaging methodology will be expanded to allow for more ef?cient imaging near a wider variety of metallic implants. In addition, an alternative approach to diffusion-weighting in multi-spectral imaging is proposed for development and exploration. The co-development of these two strategies to diffusion-weighted multi-spectral imaging provides an opportunity for controlled identi?cation of an optimal mechanism to move forward in large-cohort clinical trials of diffusion- weighted MSI near metal implants. Evaluation tests of the proposed technical approaches are proposed in phantom and human studies. Metrics and targets are outlined for comparison purposes to assess diffusion quanti?cation accuracy as well as acquisition time ef?ciency.